Updated branching ratios and $CP$ asymmetries in $D \to PV$ decays

TL;DR

This paper updates the analysis of $D o PV$ decays using a refined FAT approach, incorporating SU(3) breaking and high-precision data to improve predictions of branching ratios and $CP$ asymmetries, guiding future experiments.

Contribution

It introduces a more precise FAT analysis with updated parameters and strong phases, enhancing the understanding of nonfactorizable effects and $CP$ asymmetries in charm decays.

Findings

Refined parameters for $C$, $E$, and $A$ diagrams with improved precision.

Predictions of $CP$ asymmetries reaching $ ext{O}(10^{-3})$ in several modes.

Branching ratios in good agreement with current data and future experimental tests.

Abstract

Motivated by extensive new high-precision experimental data, we present an updated analysis of the two-body charm decays $D \to PV$ (with $P =\pi,K, \eta^{(\prime)}$ and $V =\rho, K^*, \omega, \phi$) within the factorization-assisted topological-amplitude (FAT) approach. In the framework, flavor SU(3) symmetry breaking effect is incorporated into the topological amplitudes, allowing the nonfactorizable contributions from topological diagrams to be expressed as a minimal set of universal parameters determined through a global fit to experimental data. Thanks to the sufficient data with high precision, we are now able to quantify the nonfactorizable contribution of so-called ``factorization" $T$ diagram, which is essential for explaining the observed branching ratios. The parameters for the $C$, $E$, and $A$ diagrams are also updated with significant improved precision, and notably, the resulting strong phases differ substantially from those in the earlier FAT analysis. We find that the $C$ topological amplitude features substantial nonfactorizable effects in the charm sector. These refined parameters enable predictions of significantly improved accuracy, yielding branching ratios in good agreement with current data and the latest results in topological diagram approach, and the predicted direct $\mathit{CP}$ asymmetries differ distinctly form previous FAT results due to updated strong phases. In several modes, the $\mathit{CP}$ asymmetries are predicted to reach $\mathcal{O}(10^{-3})$, thereby making them promising observables for future high-precision experiments at LHCb, BESIII and Belle II. Predictions for unobserved decay modes, especially those with branching fractions of order $10^{-4}\sim10^{-3}$, are also provided for forthcoming experimental tests.